Cucn-mediated one pot production of cinnamonitrile derivatives

ABSTRACT

The present invention discloses a cheaper and practical protocol for the construction of a wide variety of o-cyanocin-namonitrile and their structural analogues that proceeds with good yields in a single step using CuCN as the only reagent.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention relates to a cheaper and practical protocol forthe preparation of compounds of formula A, its isomers and theirstructural analogues in a one pot and single step via hydrocyanationreaction of compound of general formula I with good yields.

2. Description of Prior Art

Aryl nitriles can be prepared by the cyanation of aryl halides with anexcess of copper(I) cyanide in a polar high-boiling solvent such as DMF,nitrobenzene, or pyridine at reflux temperature using Rosenmund-vonBraun Reaction.

Alpha beta unsaturated nitriles are versatile reagents which have beenused extensively in the synthesis of heterocycle compounds. Synthesis ofcinnamonitrile by treating benzaldehyde with acetonitrile in presence ofalkali is disclosed in Organic Syntheses, Coll. Vol. 7, p.108 (1990);Vol. 62, p.179 (1984). An article titled “Efficient One-Pot Synthesis of2-Amino-4H-chromenes Catalyzed by Ferric Hydrogen Sulfate and Zr-BasedCatalysts of FI” published in Synthesis and Reactivity in Inorganic,Metal-Organic, and Nano-Metal Chemistry, Volume 41, Issue 9, 2011,wherein, the preparation of α-cyanocinnamonitrile is carried by thecondensation of aldehyde with malononitrile to affordα-cyanocinnamonitrile derivatives by Knoevenagel addition reaction.Decarboxylation of E-3-phenyl-2-cyanopropenoic acid in dimethylsulfoxide containing sodium bicarbonate, lithium chloride, and water inmolar excess afforded, with high stereospecificity, Z-cinnamonitrile isdisclosed in an article titled “Stereochemistry of thedealkoxycarbonylation of methyl α-cyanocinnamate and of thedecarboxylation of the corresponding cyano acid: a facilestereoselective route to Z-cinnamonitrile” Tetrahedron Letters, Volume24, Issue 36, 1983, Pages 3835-3838. Article titled, “HYDROCYANATION OFALKENES AND ALKYNES” by T. V. (BABU) RAJANBABU reports that Hydrogencyanide itself is relatively unreactive, but in the presence of acatalyst HCN adds to carbonyl compounds, alkenes, and alkynes, offeringa direct and economical way to such organonitrile intermediates.

In a scientific article titled, “The preparation of aryl nitriles” byDIANDRA M. RUDZINSKI, NICHOLAS E. LEADBEATER in chimica oggi/ChemistryToday-vol. 29 n. 4 July/August 2011, reports the process of CYANATIONthrough Modem methodologies by using catalytic amounts oftransition-metal complexes, together with less toxic cyanide sourcesmaking chemistry more efficient, applicable and safer.

Article titled, “Mechanistic Insights into the Hydrocyanation Reaction”by Laura Bini in page 121, reports the hydrocyanation of styrene inpresence of CuCN giving 78% conversion and 88% selectivity with a ratioof 13:87 for linear and branched nitriles and a yield of 73-80%.cinnamonitrile and their esters have wide range of industrialapplications for example in cosmetic industry.

Although few inventions have been made in the synthesis ofcinnamonitrile they require multiple steps with consumption of largequantities of hazardous chemicals with less efficiency and narrowsubstrate scope. Therefore, there is a need in the art to provide analternate and effective synthesis to provide a library ofcinnamonitrile. Further it would be desirable have a process ofsynthesis of cinnamonitriles by a convenient single step one potprocess. Specifically, it would be desirable to provide a simple processfor the conversion of dibromovinyl benzenes to their correspondingcinnamonitriles.

OBJECTS OF INVENTION

The main object of the present invention is to provide an effective onepot synthesis, single step for the preparation of cinnamonitrilederivatives via hydrocyanation reaction with good yields.

SUMMARY OF INVENTION

In an embodiment of the present invention a one pot, single step processfor the preparation of compound of formula A and its isomers, startingfrom compounds of formula I,

-   -   Wherein,    -   R¹ is hydrogen;    -   R² is selected from H, OMe, OTs, OBn;    -   R³ is selected from H, OMe, OTs, OBn, NO₂;    -   R⁴ is selected from H, OMe, F;    -   R⁵ is selected from H, NO2, BR;    -   R⁵′ is selected from H, NO2, CN;    -   R² and R³ can together be selected as —O—CH₂-O—;        comprising the steps of reacting compound of formula I with CuCN        in DMF, under reflux in presence of N₂ atmosphere to obtain the        desired compound of formula A in the range of 50-90% yield.

In another embodiment of the present invention, the said compound offormula I and CuCN are in the ratio of 1:2 to 1:3.

In yet another embodiment of the present invention , isomers of compoundof formula A are trans and cis isomers in the ratio of 3:1 to 10:1.

In yet another embodiment of the present invention, the reaction iscarried out at a temperature ranging from 140 to 160° C.

In yet another embodiment of the present invention, the reaction iscarried out for a time ranging from 10 to 15 hours.

DETAILED DESCRIPTION OF THE INVENTION:

In accordance with the above, the instant invention provides one potsingle step synthesis, of CuCN-mediated hydrocyanation reaction, for thepreparation of cinnamonitrile derivatives. The CuCN-mediatedhydrocyanation reaction according to the invention essentially makes useof the conditions prescribed for Rosenmund-von Braun Reaction.

The process of the present invention is easier to adopt on industrialscale for preparation of library of cinnamonitrile derivatives as itinvolves a one pot hydrocyanation reaction. The process of the instantinvention is cost effective when compared to the existing methods as itinvolves CuCN, a very cheaper reagent, easy to maintain and perform athigher scales, showed remarkably broad substrate scope and goodfunctional group tolerance and do not cause much effluent generation.The procedure tolerates a series of functional groups, such as methoxyl,fluoro etc.

In an aspect of the invention, cinnamonitrile derivative of formula (A)is represented as enlisted herein:

-   -   Wherein,    -   R¹ is hydrogen;    -   R² is selected from H, OMe, OTs, OBn; (Ts=Tosyl, Bn=Benzyn))    -   R³ is selected from H, OMe, OTs, Obn, NO₂;    -   R⁴ is selected from H, OMe, F;    -   R⁵′ is selected from H, NO2, CN;    -   R² and R³ can together be selected as —O—CH₂-O—;

In an aspect of the invention, the compound of Formula I is

-   -   Wherein,    -   R¹ is hydrogen;    -   R² is selected from H, OMe, OTs, OBn;    -   R³ is selected from H, OMe, OTs, OBn, NO₂;    -   R⁴ is selected from H, OMe, F;    -   R⁵ is selected from H, NO2, BR ;    -   R² and R³ can together be selected as —O—CH₂-O—;

In a preferred embodiment, the invention discloses preparation ofcinnamonitrile derivatives, which process comprises treating substituted2,2-dibromovinyl benzene with CuCN in DMF at 150° C. for 10-15 hrs toobtain substituted cinnamonitrile derivative in a single step. The bromovinyl benzene and CuCN are used in the ratio of 1:2 to 1:3 in theprocess described herein. The reaction is shown in scheme below:

Wherein, R is selected from F, H, Br, OMe, OTs, OBn, NO₂, —O—CH₂-O—.Accordingly, in a preferred embodiment, a typical procedure is disclosedfor the preparation of 3-(2-cyano-4,5-dimethoxyphenyl)acrylonitrile byrefluxing a stirred solution of1-bromo-2-(2,2-dibromovinyl)-4,5-dimethoxybenzene or1-bromo-2-ethynyl-4,5-dimethoxybenzene in DMF with the addition of CuCNunder N₂ atmosphere for 12 h (monitored by TLC). The reaction mixture iscooled to room temperature followed by workup of the reaction mixture toobtain crude products which can be purified by column chromatography toget 3-(2-cyano-4,5-dimethoxyphenyl)acrylonitrile in 63% yield.

The present invention discloses preparation of a library of compounds ofcinnamonitrile derivatives by employing the process of the presentinvention. The reactants and the compounds obtained by the process ofthe invention is described herein below in tables 1.

TABLE 1

Products S. Reactants (trans/ Yield^(a) no. R¹ R² R³ R⁴ R⁵ R^(5′) cis)(%)  1 H H H H H H 4/1 53  2 H H OMe H H H 3/1 52  3 H H NO₂ H H H 4/186  4 H H H H NO₂ NO₂ 4/1 88  5 H H H H Br CN 10/1  56  6 H OMe H H BrCN 4/1 73  7 H OMe OMe H Br CN 3/1 82  8 H OMe H OMe Br CN 3/1 71  9 HOMe OMe OMe Br CN 4/1 73 10 H OBn OMe H Br CN 4/1 57 11 H OBn OBn H BrCN 4/1 71 12 H OTs OMe H Br CN 4/1 52 13 H H H F Br CN 3/1 63 14 H—O—CH₂—O— H Br CN 3/1 71 ^(a)Combined isolated yield after columnchromatographic purification.

EXAMPLES

The following examples, which include preferred embodiments, will serveto illustrate the practice of this invention, it being understood thatthe particulars shown are by way of example and for purpose ofillustrative discussion of preferred embodiments of the invention

1. General Information

Solvents were purified and dried by standard procedures before use;petroleum ether of boiling range 60-80° C. was used. Melting points areuncorrected. Infrared spectra were recorded on Shimadzu FTIR-8400spectrometer. ¹H NMR and ¹³C NMR were recorded on Bruker AV-200, AV-400& AV-500 NMR spectrometers, respectively. Elemental analysis was carriedon a Carlo Erba CHNS-O analyzer. Purification was done using columnchromatography (230-400 mesh).

2. Experimental Section

A General Experimental Procedure for the Preparation of SubstitutedCinnamonitrile (2a-n)

The dibromoolefines 1(a-n) (1 mmol) was taken in dry DMF (10 mL) andCuCN (3 mmol) was added to it and the entire solution refluxed under N₂for 12 h (monitored by TLC). The reaction mixture was then cooled toroom temperature, and diluted with water (30 mL) and EtOAc (25 mL). Theorganic layer was separated and the aqueous layer was extracted withEtOAc (3×20 mL). The combined organic extracts were washed with brineand dried over anhyd. Na₂SO₄ and concentrated under reduced pressure togive crude products which was purified by column chromatography [silicagel (230-400 mesh) and petroleum ether: EtOAc (7:3) as an eluent] togive substituted cinnamonitrile (a-i) in 73-82% yield.

3. Experimental Data Cinnamonitrile (2a)

Yield: 72%; IR (CHCl₃, cm⁻¹): υ_(max)965, 1030, 1107, 1244, 1301, 1601,1624, 2217; ¹H NMR (200 MHz, CDCl₃): δ5.44 (d, J=12.2 Hz, 0.23H)Z-isomer , 5.87 (d, J=16.6 Hz, 1H) E-isomer, 7.11 (d, J=12.2 Hz, 0.42H)Z-isomer, 7.40-7.47 (m, 7H), 7.80 (dd, J=2.4, 3.6 Hz, 0.5H), 7.87;¹³C-NMR (50 MHz, CDCl ₃): δ94.9, 96.3, 117.8, 127.2, 128.1, 128.7,128.8128.9, 129.2, 130.7, 131.0, 133.4, 148.3, 150.2; Analysis: C₉H₇Nrequires C, 83.69 ; H, 5.46 ; N, 10.84; found: C, 83.49; H, 5.63; N,10.24%.

3-(4-methoxyphenyl)acrylonitrile (2b)

Yield: 78%; IR (CHCl₃, cm ⁻¹): υ_(max) 985, 940, 1041, 1134, 1296, 1454,1512, 1590, 2219; ¹H NMR (200 MHz, CDCl₃): δ3.84 (s, 3H), 3.85 (s, 3H),5.28 (d, J=12.2, 1H) Z-isomer, 5.70 (d, J=16.5 Hz, 0.82H) E-isomer,6.87-7.05 (m, 5H), 7.26 (d, J=3.0, 1H), 7.38 (d, J=8.84, 2H), 7.78 (d,J=8.84, 2H),; ¹³C-NMR (50 MHz, CDCl₃): δ55.1, 55.2, 91.6, 93.1, 114.0,114.3, 126.1, 126.3, 128.8, 130.7, 147.7, 149.6, 161.4, 161.8; Analysis:C₁₀H₉NO requires C, 75.45; H, 5.70; N, 8.80; found: C, 75.65; H, 5.47;N, 8.71%.

3-(4-(methylthio)phenyl)acrylonitrile (2c)

Yield: 74%; IR (CHCl₃, cm⁻¹): υ_(max) 752, 992, 1090, 1215, 1279,1297,1520, 2219; ¹H NMR (200 MHz, CDCl ₃): S 2.50 (s, 5H), 5.35 (d,J=12.0 Hz, 0.48H) Z-isomer, 5.80 (d, J=16.6 Hz, 1H) E-isomer, 7.03 (d,J=12.0 Hz, 0.48H) Z-isomer, 7.18-7.36 (m, 6H), 7.72 (d, J=8.4 Hz, 1H);¹³C-NMR (50 MHz, CDCl₃): δ14.6, 93.3, 94.7, 117.3, 118.0, 124.6, 125.3,125.5, 127.4, 129.1, 129.6, 129.7, 142.9, 143.1, 147.5, 149.4; Analysis:C₁₀H₉NS requires C, 68.53; H, 5.18; N, 7.99, S, 18.3 found: C, 68.69; H,5.18; N, 7.56%.

3-(4-(trifluoromethyl)phenyl)acrylonitrile (2d)

Yield: 73%; IR (CHCl₃, cm⁻¹): υ_(max) 816, 921, 1045, 1276, 1296, 2116;¹H NMR (200 MHz, CDCl₃): δ5.60 (d, J=12.1 Hz, 0.82H) Z-isomer, 5.98 (d,J=16.6 Hz, 1H) E-isomer, 7.18 (d, J=12.1 Hz, 0.82H) Z-isomer, 7.43 (d,J=16.6 Hz, 1H) E-isomer, 7.57 (d, J=8.8 Hz 2H), 7.69 (t, J=6.57 Hz, 3H),7.91 (d, J=8.8 Hz 2H); ¹³C-NMR (50 MHz, CDCl₃): δ97.9, 99.2, 116.4,117.1, 102.8, 125.6, 125.7, 125.8, 125.9, 126.0, 126.1, 127.5, 129.0,136.6, 146.8, 148.5; Analysis: C₁₀H₆F₃N requires C, 60.92; H, 3.07; F,28.91; N, 7.01 found: C, 60.71; H, 3.11; N, 6.96%.

3-(4-fluorophenyl)acrylonitrile (2e)

Yield: 76%; IR (CHCl₃, cm⁻¹): υ_(max) 814, 912, 1011, 1064, 1246, 1512,2219; ¹H NMR (200 MHz, CDCl₃): δ5.44 (d, J=12.2 Hz, 1H), Z-isomer, 5.80(d, J=16.1 Hz, 0.84H) E-isomer, 7.05-7.17 (m, 5), 7.36 (d, J=16.1 Hz,0.84H) E-isomer, 7.41-7.48 (m, 2H), 7.79-7.86 (m, 2H; ¹³ 37 C-NMR (50MHz, CDCl₃): δ97.5, 115.4, 117.0, 128.0, 130.8, 146.2, 162.1 Analysis:C₉H₆FN requires C, 73.46; H, 4.11; F, 12.91; N, 9.52; found: C, 73.62;H, 4.32; N, 9.42%.

3-(4-chlorophenyl)acrylonitrile (2f)

Yield: 81%; Colorless oil; IR (CHCl₃, cm⁻¹): υ_(max) 772, 915, 1052,1124, 1206, 1512, 2121; ¹H NMR (200 MHz, CDCl₃): δ5.83 (d, 1H, J=16.5Hz), 7.3(d, J=16.5 Hz, 1H), 7.38 (s, 4H; ¹³C-NMR (50 MHz, CDCl ₃):δ97.1, 117.5, 128.4, 129.3, 131.9, 137.2, 148.8; Analysis: C₉H₆ClNrequires C, 66.07; H, 3.70; Cl, 21.6; N, 8.56; found: C, 66.21; H, 6.62;N, 8.32%.

3-(2-nitrophenyl)acrylonitrile (2 g)

Yield: 88%; IR (CHCl₃, cm⁻¹): υ_(max) 767, 1249, 1604, 1575, 1673, 2118;¹H NMR (200 MHz, CDCl₃): Z-isomer δ5.72 (d, J=11.7 Hz, 1H), 7.61-7.90(m, 4H), 8.22 (d, J=8.0 Hz, 1H) ; ¹³C-NMR (50 MHz, CDCl₃): δ101.2,115.7, 125.2, 129.5, 130.6, 130.9, 134.2, 146.3, 147.2; E-isomer; δ5.85(d, J=16.4 Hz, 1H), 7.56-7.76 (m, 3H), 7.96 (d, J=16.4 Hz, 1H), 8.13(dd, J=1.5,8.09 Hz,1H); ¹³C-NMR (50 MHz, CDCl₃): δ101.7, 116.7, 125.3,128.6, 129.7, 131.2, 133.9, 146.4, 147.5; Analysis: C₉H₆N₂O₂ requires C,66.07; H, 3.47; N, 16.09; found: C, 66.03; H, 3.13; N, 16.89%.

3-(4-nitrophenyl)acrylonitrile (2h)

Yield: 86%; IR (CHCl₃, cm⁻¹): υ_(max) 736, 853, 1249, 1604, 1546, 1665,2116; ¹H NMR (200 MHz, CDCl₃): Z-isomer δ5.75 (d, J=11.6 Hz, 1H), 7.32(d, J=11.6 Hz, 1H), 7.56 (d, J=8.1 Hz, 1H), 8.14(d, J=8.1 Hz, 1H) ;¹³C-NMR (50 MHz, CDCl₃): δ99.2, 117.0, 122.2, 127.3, 141.3, 146.1,147.6, 134.2, 146.3, 147.2; E-isomer; δ6.05 (d, J=16.6 Hz, 1H), 7.47 (d,J=16.6 Hz, 1H), 7.63 (d, J=8.8 Hz, 2H), 8.28 (d, J=8.8 Hz, 2H); ¹³C-NMR(50 MHz, CDCl₃): δ101.2, 116.7, 124.4, 128.1, 139.2, 147.6, 149.2;Analysis: C₉H₆N₂O₂ requires C, 66.07; H, 3.47; N, 16.09; found: C,66.012; H, 3.32; N, 16.32%.

2-(2-cyanovinyl)-4,5-dimethoxybenzonitrile (2i)

Yield: 82%; IR (CHCl₃, cm⁻¹): υ_(max) 886, 927, 960, 1037, 1290, 1488,1503, 2123; ¹H NMR (200 MHz, CDCl₃): E-isomer; δ3.95 (s, 3H), 3.98 (s,3H), 5.98 (d, J=16.5 Hz, 1H), 7.01 (s, 1H), 7.09 (s, 1H), 7.65 (d,J=16.5 Hz, 1H); ¹³ C-NMR (50 MHz, CDCl₃): δ54.3, 93.7, 102.2, 106.7,112.6, 115.1, 116.1, 128.2, 142.9, 149.2, 150.8; ¹H NMR (200 MHz,CDCl₃): Z-isomer; δ3.96 (s, 3H), 4.02 (s, 3H), 5.60 (d, J=12.1 Hz, 1H),7.10 (s, 1H), 7.46 (d, J=12.1 Hz, 1H), 7.99 (s, 1H); ¹³C-NMR (5 0 MHz,CDCl₃): δ56.3, 96.9, 106.0, 109.6, 114.1, 116.8, 130.3, 143.6, 150.9,152.6; Analysis: C₁₂H₁₀N₂O₂ requires C, 67.28; H, 4.71; N, 13.08; found:C, 67.79; H, 4.12; N, 13.46%.

2-(2-cyanovinyl)-4-methoxybenzonitrile (2j)

Yield: 73%; IR (CHCl₃): 547, 709, 767, 833, 856, 1023, 1247, 1597, 2211cm⁻¹; ¹H NMR (200 MHz, CDCl₃): Z-isomer; δ3.94 (s, 3H), 5.70 (d, J=12.13Hz, 1H), 7.01 (dd, J=2.53, 8.72 Hz, 1H), 7.49 (d, J=12.13 Hz, 1H), 7.63(d, J=8.72 Hz, 1H), 7.86 (d, J=2.53 Hz, 1H); ¹³C NMR (CDCl₃): δ55.80,99.94, 104.95, 112.23, 116.10, 116.83, 117.88, 134.57, 137.77, 144.00,162.91 ¹H NMR (200 MHz, CDCl₃): δ3.91 (s, 3H), 6.07 (d, J=16.54 Hz,1H),7.00 (dd, J=2.53, 8.59 Hz, 1H), 7.09 (d, J=2.53 Hz, 1H), 7.62 (d,J=16.54 Hz, 1H), 7.64 (d, 8.59 Hz, 1H); ¹³ C NMR (CDCl₃): δ55.79,101.60, 104.12, 111.95, 116.67, 116.86, 135.25, 137.77, 145.53, 162.94;Analysis: C₁₁H₈N₂O₁ requires C 71.73, H 4.38, N 15.21, found C 70.18, H4.16, N 14.97%.

6-(2-cyanovinyl)-2,3,4-trimethoxybenzonitrile (2k)

Yield: 71%; IR (CHCl₃, cm⁻¹): υ_(max) 791, 845, 964, 1052, 1239, 1412,1472, 1533, 1664, 2117; ¹H NMR (200 MHz, CDCl₃): Z-isomer; δ3.93 (s,3H), 4.00 (s, 3H), 4.07, (s, 3H), 5.64 (d, J=12.2 , 1H), 7.44 (d, J=12.2, 1H), 7.71 (s, 1H); ¹³ C-NMR (50 MHz, CDCl₃): δ56.4, 61.5, 61.8, 98.4,101.1, 106.5, 114.1, 116.6, 132.0, 143.5, 143.7, 155.9, 157.3; ¹H NMR(200 MHz, CDCl₃): E-isomer; δ3.91 (s, 3H), 3.96 (s, 3H), 4.06, (s, 3H),6.03 (d, J=16.5 , 1H), 7.81 (s, 1H), 7.59(d, J=16.5, 1H), ¹³C-NMR (50MHz, CDCl₃): 56.3, 61.1, 61.7, 100.3, 104.6, 114.1, 116.9, 132.2, 143.6,145.3, 155.8, 157.4 Analysis: C₁₃H₁₂N₂O₃ requires C, 63.93; H, 4.95; N,11.47; found: requires C, 63.71; H, 4.51;

2-(2-cyanovinyl)-4,6-dimethoxybenzonitrile (21)

Yield: 71%; IR (CHCl₃, cm⁻¹): υ_(max) 791, 845, 964, 1052, 1215, 1239,1240, 1412, 1472, 1533, 1664, 2970, 3332, 3451; ¹H NMR (200 MHz, CDCl₃):δ3.90 (s, 3H), 3.94 (s, 3H), 6.09 (d, J=16.5 , 1H), 6.52 (s, 1H), 6.64(s, 1H), 7.61, (d, J=16.5, 1H); ¹³C-NMR (50 MHz, CDCl₃): δ55.9, 56.3,94.6, 100.1, 101.9, 103.2, 114.4, 116.7, 138.7, 145.8, 163.6, 164.2;Analysis: C₁₂H₁₀N₂O₂ requires C, 67.28; H, 4.71; N, 13.08; found:requires C, 67.61; H, 4.42; N, 13.15.

4,5-bis(benzyloxy)-2-((E)-2-cyanovinyl)benzonitrile (2m)

Yield: 71%; IR (CHCl₃, CM⁻¹): υ_(max) 752, 991, 1091, 1244, 1279, 1296,1454, 1462, 1512, 1590, 2219; ¹H NMR (200 MHz, CDCl₃): δ5.21 (s, 2H),5.29 (s, 2H), 5.54 (d, J=12.2 , 1H), 7.13 (s, 1H), 7.32-7.41 (m, 9H),7.48, (d, J=7.3, 2H), 8.02, (s, 1H); ¹³C-NMR (50 MHz, CDCl₃): δ71.0,71.2, 97.0, 106.1, 111.7, 116.9, 127.2, 127.6, 128.4, 128.5, 128.7,128.8 130.4, 135.5, 143.6, 150.5 152.4; Analysis: C₂₄H₁₈N₂O₂ requires C,68.67; H, 4.95; N, 7.65; found: requires C, 68.54; H, 4.85; N, 7.12.

6-(2-cyanovinyl)benzo[d][1,3]dioxole-5-carbonitrile (2n)

Yield: 71%; IR (CHCl₃, cm⁻¹): υ_(max) 791, 841, 962, 1034, 1245, 1412,2217; ¹H NMR (200 MHz, CDCl₃): δ5.62 (d, J=11.9 , 1H), 6.17 (s, 2H),7.10 (s, 1H), 7.45, (d, J=11.9 , 1H) 7.84, (s, 1H); ¹³C-NMR (50 MHz,CDCl₃): δ98.08, 103.1, 107.6, 11.8, 116.2, 116.5, 129.9, 132.4, 143.3,149.7, 151.9; Analysis: C₁₁H₆N₂O₂ requires C, 66.67; H, 3.05; N, 14.14;found: requires C, 66.61; H, 3.49; N,

ADVANTAGES OF INVENTION

-   -   1. One pot process    -   2. Cheaper, safe and efficient    -   3. O-cyanocinnamonitrile and their esters have wide range of        industrial applications for example in cosmetic industry.    -   4. Broad substrate scope and good functional group tolerance    -   5. Less amount of effluent generate

1. A one pot, single step process for the preparation of compound ofgeneral formula A and its isomers,

starting from compounds of formula I,

wherein, R¹ is hydrogen; R² is selected from H, OMe, OTs, OBn; R³ isselected from H, OMe, OTs, OBn, NO₂; R⁴ is selected from H, OMe, F; R⁵is selected from H, NO₂, BR; R⁵′ is selected from H, NO₂, CN; R² and R³can together be selected as —O—CH₂-O—; comprising the steps of reactingcompound of formula I with CuCN in DMF, under reflux in presence of N₂atmosphere to obtain the desired compound of formula A in the range of50-90% yield.
 2. The process according to claim 1, wherein said compoundof formula I and CuCN are in the ratio of 1:2 to 1:3.
 3. The processaccording to claim 1, wherein said isomers of compound of formula A aretrans and cis isomers in the ratio of 3:1 to 10:1.
 4. The processaccording to claim 1, wherein the reaction is carried out at atemperature ranging from 140 to 160° C.
 5. The process according toclaim 1, wherein the reaction is carried out for a time ranging from 10to 15 hours.
 6. (canceled)